Light trapping with titanium dioxide diffraction gratings fabricated by nanoimprinting

摘要

Dielectric scattering structures are a promising way of trapping light in solar cells. Titanium dioxide is a particularly attractive candidate material because of its high refractive index and ability to be deposited on a finished solar cell. Here, we present an experimental demonstration of photocurrent enhancement in thin film recrystallised silicon solar cells using TiO_2 pillar arrays fabricated on the rear of the cells using nanoimprint lithography. A short circuit current enhancement of 19% is measured experimentally, and excellent agreement with numerical simulations is obtained. We show numerically that by replacing the Ag capping present on the cells with a detached rear Ag back reflector, the enhancement could reach 37%.